Firefox 16 adds more developer muscle, but Mac OS features lag

A new dev toolbar and command line for Firefox, but Lion gestures are AWOL.

Mozilla has announced the public availability of Firefox 16, the latest version of its open-source web browser. While this version is light on new features that most users will notice—and missing some features many faithful users have been expecting—there are some major additions under the hood that will make Firefox 16 a better platform for developing apps for both the desktop browser and mobile web.

As we've reported, Firefox 15 included a whole host of user experience features, including some impressive support for web-based gaming. Firefox 16 is focused more on pushing forward the browser's support for advanced Cascading Style Sheets features and HTML 5 programming interfaces, as well as a pair of web APIs suited specifically to tablets and mobile devices. There's also a new feature of the browser that will appeal to both developers and power users: a command line that drives many of the browser's internal tools.

Underneath, there's a performance tweak to the garbage collection in Firefox's JavaScript engine. There's also a new security feature rolled out in Firefox 16, called "opt-in activation," that will allow Mozilla to reach out and configure users' browsers to prompt them to allow out-of-date or known vulnerable browser plug-ins from running.

But what's missing from Firefox 16 is just as important—or perhaps more important—than what made it into this release. Firefox 16 still (at least officially) lacks a built-in PDF reader—while reading PDFs is supported through a browser add-in, the internal reader is still experimental. And more notably for Mac users, a whole raft of bug fixes for support of Mac OS X Lion and Mountain Lion have missed release—without any indication of when they'll finally be rolled in.

By your command

The Developer Command Line is integrated into Firefox's new Developer Toolbar, which also gives users quick access to Firefox's integrated Web console, JavaScript debugger, and page element inspection tools. Normally out of view, the toolbar can be summoned by pressing the Shift and F2 keys.

Enlarge/ The command line box in Firefox 16, indicated by the arrow, allows developers and power-users to quickly access key features of the browser's development environment and settings.

The commands are all documented within the Command Line's own help system. In addition, as you type into the Command Line bar, Firefox autocompletes commands, and offers syntactic help in completing them.

Each of the developer tools that are launchable from the Developer Toolbar are also fully wired into the command line, so developers can keep their fingers on the keyboard, using text commands to launch and manipulate the Web console and JavaScript debugger, to configure break points in JavaScript code, and make changes to various attributes of the page they're working on. The command line can also be used with the Inspector to launch specific views of the page contents—such as the 3D "Tilt" visualization of a page's elements, which can be opened and rotated from the command line.

There are some features of the command line tool that will be useful to non-developers as well. You can also use the command line to list and clear cookies, change the settings for browser add-ons, restart the browser, and even take screenshots of a browser page.

Changes under the hood

The major performance improvement in Firefox 16 is the introduction of incremental garbage collection. Firefox's JavaScript engine previously collected memory from scripts that were no longer running in big, long-running blocks; now it performs the culling in smaller segments to avoid a performance hit.

Out-of-date plugins (such as Flash players, for example) have long been a weak point in browser security. In Firefox 14, Mozilla introduced a feature that allowed users to configure all plug-ins to require user authorization to launch, called "click to play," that would at least allow security-conscious users to know when a web page was trying to execute content in one of them. The "click-to-play" feature isn't exactly something that is easily configured by an average user right now—it's buried in the about:config advanced configuration screen accessible through the browser itself.

Enlarge/ An example of a blocked plug-in—Flash on the YouTube homepage.

The opt-in feature has been extended in Firefox 16 to allow Mozilla to remotely configure "click to play" for specific plug-ins based on information from their developers. This isn't a feature users can configure—it's specifically wired into Mozilla's update system.

For example, in the event of a Flash player vulnerability, Adobe could pass an alert through Mozilla to users, prompting users when a site tries to launch the plug-in with an alert—essentially nagging them until they update the out-of-date software, while giving them the opportunity to avoid malicious content in the meantime. A similar feature is already part of Google Chrome.

What's missing for Mac OS X?

While the inline PDF reader is currently slotted for Firefox 18—which will likely be released before the end of the year—the Mac OS X fixes have dropped completely off Mozilla's release tracking radar. Some of the issues have been resolved, such as the use of Lion's (and Mountain Lion's) native scrollbars, and support for full-screen mode (though I experienced some bugs in full screen support when using it on a MacBook with a second, external monitor).

Also, Firefox 16 finally adds support for the VoiceOver voice-assisted navigation feature in Mac OS X, allowing users to navigate through content from their keyboard and describing content by voice as it's moused over. But other interface elements, such as support for multitouch gestures like pinching to zoom in and out (already supported on Firefox's mobile browser) and the three-finger double-tap to bring up a dictionary definition of a word), remain untouched.

The same is true for the swiping gesture for moving back and forth through history, as is supported in Safari. (Chrome supports these gestures, but without the animation used by other applications.)

Mac interface purists holding out for those features won't be happy anytime soon. That's because the bug requests to make Firefox more Lion-friendly haven't even been assigned yet. Considering there's a whole new set of gesture-based fixes that will be needed to support Windows 8, it's not likely they'll be getting much priority.

Promoted Comments

If I were on the Mozilla team, I would assign resources to the Windows version of Firefox too. OS X users seem mostly happy with Safari.

Why would someone switch to Firefox and be treated as a second-rate citizen? We had enough of that from Adobe with Flash and Acrobat.

You use a product with second rate marketshare, you should be prepared to be treated like second rate citizens. I don't know why this is a foreign concept to anyone. I have to deal with it all the time with my Windows Phone. You should know what you're getting into when you pick a platform that is vastly outperformed in market penetration and developer interest when you go to use it.

When someone asks why Firefox isn't picking up in OS X, it's because they're not doing anything to attract users. Firefox will be a second-rate browser on the Mac because that's all Mozilla wants to make.

Usually when a business wants to expand into an existing market, it works hard to attract that market. If they don't care to do that, then they'll be an also-ran.

They're still working to attract users even on the Windows platform. They don't have any lack of potential users there even to this day. There's a reason the Windows platform is the Priority 1 for development. You can argue about it and hate it all day but it's simple cold hard logic. They devote the most resources to the platform with the most users.

Firefox used to be my go-to browser on my Macs and my PCs. It was especially useful for viewing sites on the Mac that seemed to be coded on Windows for Windows. Except for the insecure ActiveX garbage, Firefox made IE-targeted sites work well on the Mac. Of course, on the PC, Firefox was/is the more secure choice.

As web sites moved away from IE-specific coding, and toward open standards, Firefox became less necessary, and Safari became universally useful. And then came Chrome, as well.

You're seriously expecting me to believe that a talented organization like Mozilla cannot fix bugs, or even acknowledge them, for Mac OS 10.7? (Lion was first released to developers over 18 months ago.) That's not a market share decision. That's a lack of interest, period. That's telling your loyal Mac-using customer, "We don't need you so much anymore." Are they treating their Linux version with the same disdain?

Looks to me like they're sinking all their brainpower into the Firefox Mobile OS. I guess because Meego needs a competitor. Or something.

Sean Gallagher / Sean is Ars Technica's IT Editor. A former Navy officer, systems administrator, and network systems integrator with 20 years of IT journalism experience, he lives and works in Baltimore, Maryland.